So far, it seems about 15% of the established, permanent teachers in my school will not be coming back in September to my Dublin school. The refusal of the school to grant a career break, and promotions to elsewhere in the education system were factors. Additionally, abuse of social media is increasingly an issue in teachers leaving teaching entirely as it's not a safe working environment (specifically, secret recordings made by students in class and posted online). I expect the 15% will increase by September as people currently on career break will have until the end of August to decide if they're coming back.
For the younger teachers, accommodation costs are hemorrhaging the future. They're just leaving Dublin even though in most cases the school would like them to stay. These are teachers who will lose an extra €7,000 or so per annum for extracurricular work that they wouldn't get in most schools, but that's a pittance given the money they'd save on accommodation by moving outside Dublin. I don't think any sort of London-style top-up payment for teachers in Dublin (and I am one) is going to stop this exodus from Dublin schools to cheaper parts of Ireland.
https://www.independent.ie/irish-news/flood-of-teachers-leaving-for-other-jobs-because-they-simply-cannot-afford-a-home/42430311.html
What's the situation in your school in terms of vacancies and resignations/retirements?